Heat sinks are used in conjunction with electronic device packages to dissipate heat generated by the electronic device during use into the surrounding environment so that the electronic device will not be damaged or its performance affected by the heat. Conventional electronic device packages may include transistors, diodes, resistors and the like which are typically connected to a circuit through mounting on a printed circuit board. Generally, heat sinks are constructed of a material, usually a metal such as aluminum or aluminum alloys, having a high coefficient of thermal conduction which are formed into shapes adapted to convect or radiate heat at a high rate. In order for the heat sink to operate efficiently, it must be secured to and placed in good thermal contact with the electronic device package.
Various means are used to accomplish this purpose. For instance, it is known to provide an aperture in the electronic device package and to secure it to the heat sink by a screw, bolt or other mechanical means. However, this arrangement is somewhat time-consuming and expensive because it requires hand labor. It may also be desirable to periodically or temporarily remove the device package from the heat sink, such as if the electronic device package to which the heat sink is secured is being replaced or repaired. For this purpose heat sinks have been developed having resilient spring clips which frictionally engage the electronic device package yet allow the heat sink to be quickly and easily attached or removed from the electronic device package. Such clips may be integrally formed with the heat sink or may be constructed separately and then bonded to the heat sink.
As circuit assemblies become more complex, assembly becomes more time-consuming. Thus it is desirable that use of loose hardware be avoided as much as possible to reduce assembly time. It is also desirable that assembly devices such as clips for mounting device packages on circuit boards be readily adaptable for automated assembly and that such mounting devices be useful for a wide variety of packages on a wide variety of heat sinks.
Many heat sinks conventionally include a device-mounting clip which is either an integral part of, bonded to or bolted to the heat sink. Thus each heat sink and mounting clip comprises a single part which permits little flexibility in stocking requirements of circuit assemblers. A complete heat sink and clip assembly must be stocked for each device package used. Furthermore, placement of the device package on the heat sink is pre-determined by the position of the mounting clip, allowing no flexibility in locating the device package on the heat sink.